Are you using the same DB login in form builder that you used to create the function in the DB?
If yes then I suggest you retry the import using the 10g export utility like Mahesh told you to.
If that still doesn't work then your best bet would be to raise the issue with oracle support.

All Exp/Imp does is get the metadata/data and recreate in target.
And you did it manually and it compiled. Right?
>>But when we used any DML in Forms & Reports then showing this error.
Methinks, this is something else to do with your Forms/report environment.

>> Even I use lower version to export from Higher Version of Oracle DB then Newly introduced Data Type might not be Supported By Same.

Export/import is always meant to be used for moving data around.
Not for upgrade.
If one still still chooses to, there are specific scripts /stages to be used ( in case of compatibility issues). Check the good old document on export/import compatibility matrix.
Use the lower version to export and use the target version to import.

Step back from obsessing about specific utilities.
If/when an application implements an application using a feature like BINARY DOUBLE,
it implicitly acknowledges that this application will NEVER run on a lower version of Oracle where said feature does not exist!